Simplification of Water Quality Monitoring Methods to Study the Influence of Acid Rain on River Water

Abstract

In elementary and lower secondary schools, one of the key topics is environmental education, and in particular the water quality of precipitation (rain and snow) and river water attracts the interest of students. In this study, our goal was to allow students to obtain correct knowledge about the environment in the area where they live and to provide them with the ability to observe it. At first, the present condition of precipitation and river water was outlined in order to choose analytical quantities for monitoring those environmental water samples, and later simplified methods were proposed so that students could perform the analysis in school. The places studied were: (1) nine areas facing the Sea of Japan and (2) two rivers (Ado and Yogo) located north of Lake Biwa. The long distance flow of acidic pollutant from continental China to areas (1) was observed in the winter season. Some of the acidic pollutants flowed even to inland areas (2), and the influence of acidified precipitation on river water was observed. However, the pH level of the river water did not decrease so much, due to the buffering effect of the bicarbonate ion in the river water. Thus, three check items, pH level, electric conductivity (EC), and alkalinity (bicarbonate ion), were chosen for monitoring analytical quantities. For the former two measurements, inexpensive commercial equipment was used. On the other hand, a simplified method of measuring alkalinity was proposed: using a plastic syringe in place of a buret, a much safer solution of hydrochloric acid rather than sulfuric acid, and a BCG indicator to check the final pH level. The proposed method gave sufficiently reliable values for real river water samples, so we think that our method can be used in experiments on environmental water samples by students of elementary and lower secondary schools.